Nosocomial Bacterial Infections: Epidemiology, Source, and Antibiotic Resistance

Background: Nosocomial infections, or healthcare-associated infections (HAIs), occur in patients receiving medical services. These infections are a major global concern, resulting in significant morbidity, mortality, and lethal complications. The most common types include central line-associated bloodstream infections (BSIs), catheter-associated urinary tract infections (CAUTI), surgical site infections (SSIs), and ventilator-associated pneumonia (VAP). Effective management requires the implementation of infection control programs. This review aimed to investigate various types of nosocomial infections and antibiotic-resistant pathogens, their sources, modes of transmission, and preventive measures against hospital-acquired infections. Methods: We conducted extensive searches in online databases such as PubMed and Google Scholar to identify published studies on nosocomial infections and bacterial resistance. The search terms included "nosocomial infections", "bacterial infections with antimicrobial resistance", and "treatment strategies". Out of a total of 520 retrieved studies, 109 were selected for further review. Results: Nosocomial infections and antibiotic resistance represent major challenges in many countries, leading to significant mortality and morbidity rates. In particular, Escherichia coli, Staphylococcus aureus, and other bacterial strains have been identified as the main causes of these infections. In addition, multidrug-resistant (MDR) Pseudomonas aeruginosa is considered a critical priority pathogen contributing to nosocomial infections. The results of this study indicated that the highest levels of antibiotic resistance are observed in penicillin, cephalosporins, carbapenems, and fluoroquinolones. It is noteworthy that herbal compounds, including aloe vera and nanoparticles, may play an important role in the treatment and prevention of MDR strains. Conclusion: Nosocomial infections are increasing despite existing infection control measures, leading to higher mortality rates in critically ill patients. Furthermore, given the potential of plant compounds and nanoparticles, the results of this study could help advance new strategies for improving the monitoring and prevention of HAIs in hospitals and health centers.